Transmitting apparatus.



H. SHOEMAKBR. TRANSMITTING APPARATUS. APPLICATION FILED DBG, 23, 1905.

918,208, Patented Apr. 13, 1909.

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HARRY SHOEMAKER, OF JERSEY GllY, NEW JERSEY, ASSIGNOR TO INTERNATlONAL TELE- GRAPH CONSTRUCTION COMPANY, A CORPORATION OF NEW YORK.

TRANSMITTING APPARATUS.

Speccaton of Letters Patent.

Patented April 13, 1909.

Application filed December 23, 1905.A Serial No. 293,120.

To all whom 'it lmay concern:

Be it known that I, HARRY SHOEMAKER, a citizen ot' the United States, residing at Jersey City, in the county of Hudson and State of New Jersey, have invented a new and' useful rlransmit'ting Apparatus, ot which the following is a speciiica-tion.

sy invention relates to a telegraphic sysf tem wherein an operators key is required to instants of spark production,

interrupt or control a considerable 'amount ot electrical energy, especially of considerable current. magnitude. 'My invention resides in apparatus so disposedthat sparking at a telegraphic key, which is required to handle considerable current, as in a wireless telegraphic system, is greatly protectedv from the destructive eiiects of arcing and the clearness and sharpness ot signals transmitted is improved.

My of circuitsl and apparatus whereby the generator supplying the electricityV is always maintained under some considerable traetion of its full load corresponding with the with the result that signaling is improved in clearness; and liuctuations in load from open position of key to' closed position ofkey are reduced, with consequent reduction of strain upon the generator and its driving apparatus.'

For an illustration of a form my inven-v tion may take, reference is to` be had to the accompanying drawing.

ln the drawing A represents a looped aerial radiating conductor consisting ofthe legs a and aelectrically joined together.

at their upper ends. While a and a are shown to consist of a single conductor only, it is to be understood that any number vof conductors may be used in their stead. The lower ends of the conductors a and a.' terminate in the anchor sparkl gap terminals, the third terminal being connected with the inductance L. 'A rider r serves to include more or less ofthe inductance L in. circuit,`

andis connected 'to .the upper` end 'of second inductance L whose lower terminal connects to'earth at E. 'Serially connected between t'he rider r and the upper end ofthe inductance L are the spark-gapv g and the condensers C, C. The terminals ondary S ot' a step up transformer are-ccnnected to the spark gap g. The primary P -of said transformer is connected? in circuit reduced, whereby the key is invention resides also in adisposit-ion 'tacts the signaling is clearer ofthe secl .energy from A.A

with the generator G, preferably an alternating current generator, the key ir, inductances i, c, and the inductance I.

With key 7c in open circuit position as shown, portions of the adjustable inductanee I and z" are in series with each other and with the generator Gr and the primary P. The magnitudes 'of these. inductances are so chosen or adjusted that in vsaid position no spark passes over the gap g so that there is no radiation from the aerial conductor A. Upon closingthe key la, a ortion of the inductance i, preferably equa ingmagnitnde to the portion of the inductance'z", is thrown into parallel with the induetance z", thus permittin a much greater flow or" current in the primary P, resulting in the production of sparks at the gap g, and radiation of electro-radiant energy from the aerial conductor A. TheA current flowing when the key 7c is closed may be called the Jfull -load current.` That current is much greater than the current flowing when the key lc is open. The' partial load current, when key is open, is ot' such magnitude as to keep'the generator G and its associate driving motors sufficiently loaded to prevent serious strains, electrical or mechanical when throwing o n `full load by closing the key.

The inductances z' and z" are so d'sposed thatthey may be correspondingly and equally adjusted by theV movement of the double rider shown; or they may be independently adjustable. When the key is raised or moves to open circuit position it is not required to break the entire current of the generator G, but only a fraction thereof with resultant great reduction in sparking at the key contacts. YVith a sharper break at the key conand with reduced'sparking the wea-ring away of the key contacts is minimized.

The inductance i in circuit, when the key is open, is quite high as compared with the inductance I, so that the opening of the key throwsv into the circuit of the generator Gr a considerable reactance thus reducing the current ofthe primary Pl from a full load cnrrent to a fraction of a full load. By depressing the key however the entire inductance of the circuit is reduced by throwing the inductance z' into parallelwith i', thus permitting increased ow ofcurrent into primary P with resultant radiation of electro-radiant By this disposition the key' is required to interrunt o'r control onlyt 'a fraction of thevfull load current of the generator 'and the generator is not com elled to i stand'the shocks of removal of the ull load to zero, or the increase from zero to full load.

In lace of the self induction reactances I, i an z", non-inductive resistances may be employed and may be pro ortioned and advjustab e along the lines in icated herein for the induct'ances. v s

What I claim is:

1. In 'a signaling system, means for producing high frequency oscillations, a signaling clrcut for supplying energy thereto, a

sourcel of electrical energy 1n said circuit,

inductive resistances of different magnitudes serially connected. 1n sald circuit, and an 1nductive resistance and a key adapted to close a circuit in parallel to one of said resistances, whereby signals are transmitted.

` 2. In a slgnaling system, a signalingv circuit, a source of electricalenergy associated therewith, inductive -resistances of diierent magnitudes serially connected in said circuit, and a. circuit in parallel withlone of said resistances including. an inductive resistance lequivalent thereto, and an operators key.

3. In a signaling system,a signaling cir'- cuit, 'a-source of electrical energy associated therewith, a plurality of practically equivalent inductive resistances connected -in par; allel with each other and in series with said circuit, and a key for removing one of saidl .resistancesfrom clrcuit.

4c.` In alwireless signaling system, an oscillating circuit, a step up transformer associated therewith, a source ofv electrical energy,a plurality of inductive resistances adapted to be connected in parallel with each other and in series with said so urce and M. F. CARROLL, M.`M. AoHEsoN. 

